Chaeles e



(No Model.)

0. E. BUELL.

TELEPHONE SIGNAL. No. 251,520. Patented Dec. 27,1881;

UNITED STATES PATENT OFFICE.

CHARLES E. BUELL, OF NEW HAVEN, CONNECTICUT, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE UNITED STATES TELEPHONE MANU- FACTURING COMPANY, OF NEW YORK, N. Y.

TELEPHONE-SIGNAL.

SPECIFICATION forming part of Letters Patent No. 251,520, dated December 2'7, 1881.

Application filed June 14, 1881. (No model.) I

To all whom it may concern:

Be it known that I, CHARLES E. BUELL, a citizen of the United States, residing at New Haven,in the county of New Haven and State of Connecticut, have invented certain new and useful Improvements in Telephone-Signals; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being bad to the accompanying drawing, and to the letters or figures of reference marked thereon, which form a part of this specification.

1 My invention relates generally to thatclass of signals known in telephony as individual call systems, and having in view the calling from a central office of any one of several stations without operating the signal apparatus at any other station in the same circuit; and it relates especially to the subdivision of the said class in which the signals of the several stations in a common circuit are controlled by electro-magnets of difi'erent adjustments.

The object of the invention is to simplify and render certain and positive in its operation the apparatus used in signal systems of this class.

The accompanying drawing is a diagram illustrating the apparatus according to my in- 0 vention at three stations in the same circuit, and a central ofiice, which is provided with signal-transmitting apparatus which may be connected with several different circuits successively.

5 The numerals 1 2 3 indicate the three stations upon the same circuit, the letter M designating the bell-magnets at the several stations, and A denoting the signal-controlling magnets. Each station is provided with the 0 usual receiving and transmitting telephones.

The letters K, K and K indicate the signal-transmittin g keys at the central station.-

R, R and R are resistances, which may be connected to and disconnected from the line 7 5 by said keys.

G is a galvanometer for constantly indicating the resistance of the lines.

T is the transmitter, and T the receivingtelephone, both in a ground-wire, g, at the central station, and capable of connection with several. circuits successively by means of suitable switches, b and W.

The signal-controlling magnets A. are arranged in relation to each other so that those of more delicate adjustment, or requiring less 5 5 strength of current for their operation, are respectively more remote from the central station.

With the exception of the station farthest from the central station, the several stations are provided with devices which automatically cut off all that portion of the line beyond them outwardly from the central station, and at the same time put to earth through devices which cause the operation of a local signal that portion of the line which includes the acting apparatus and leads to the central station.

By manipulating the key K, which closes the circuit from battery to line through all the resistance-coils R R R the call-bell magnet M at station 3 is operated without making operative the electromagnets A at either of the stations 1 and 2, this resulting from the fact that the said magnet at station 3 is the most easily operated or has the slightest adj ustment of any magnet in the circuit, and may be operated by the battery-current, while all the resistances R R R are interposed in the line; but when said current is weakened by the interposition of all these resistances it is incapa- 8o ble of operating the controlling-magnets A at the other stations, which are adjusted to re quire a stronger current. In like manner the key K will close the circuit through resistances R and R and operate the controlling- 8 5 magnet A at station 2; but the current will not be strong enough on the line to operate the controlling-magnet A at station 1, as this magnet is controlled by key 3, which closes circuit through only the resistance it. 1 By the action of the electro-magnet A at either of the intermediate stations its-armature L is caused to press against a spring, 8, which forms a part of the main circuit, forcing said spring out of contact with the anvil w, 5 thus cutting off all that portion of the line outw'ardly beyond the magnet so acting.

The lever L at each of the intermediate sta- I ground wire and to the signal-bell magnet which is in said ground-wire. This closing of the circuit through the signal-bell causes it to act and call the station.

At each station the line, when there broken, should have that portion remaining connected with the central station connected with suitable resistance to compensate for the portion of the line out off, in order that the normal resistance of the line may be preserved and the signal-controllingmagnets remaining in circuit be kept in proper relation to each other and the signal-transmitting apparatus at the central station.

The signal apparatus at each of the intermediate stations is a vibratory bell, and its magnet M automatically cuts itself in and out of circuit without disturbing the continuity of the mainline circuit by diverting the current through a resistance at It equal to its own when its armature in its vibrations cuts out its helix. The resistance It may be a coil of wire or any other suitable conducting-resistance.

The cutting of themagnet in and out is performed by a point, p, projecting from the belllever to, and a spring, S, which is connected in the ground-wire g and normally bears lightly against an anvil, u", connected with the magnet-helix. When the magnet attracts its armature the point p strikes the spring 8, th rowing it off the anvil, and the current then flows from the spring over the point, the bell-lever, and resistance It to ground. The magnet, be-

' coming thus discharged,releasesits armature,

a retractin g-sprin g draws back the lever, which moves the point 12 away from the spring, which closes circuit over the anvil, and the operation is repeated, the bell b ringing until it is switched out of circuit. The bell-coil and the resistance R are arranged to efi'e'ct the compensation for the resistance of the portion of the line which may be cut off beyond the station.

The receiving and transmitting telephones may be in the ground-wire g, as shown, or in a separate ground-wire, as described, and any suitable switchessuch, for instance, as shown at D D D may be used for making the nec essary connections through contact-points, or at m, or otherwise suitably arranged. When the proper switch is operated to connect the telephones at any line-station with the central station, the signal-controlling magnet at the station is cutout; but theresistance of the telephones is sufficient to compensate for that cut out.

Each station is provided with a circuitbreaking push button or key, as at 'U, and the line, when not in use, may be normally kept connected at the central station to a light battery for signaling purposes, or magneto bells may be used.

The wires m in represent the terminals of different telephone circuits, in which the stations may be arranged as heretofore described; or any suitable number of stations may be arranged in the same circuit on the same plan. I

The switch I) at the central station may connect with either of the lines m, m, or n, and the switch I) may connect with the central-station ground-wire g, which includes a receiving and transmitting telephone, or with the line through the galvanometer and to the anvils of the transmitting-keys.

The electro-magnets A may have difierent resistances as well as different adjustments, and be utilized for varying the currents tension, and these magnets may beemployed in the ordinary manner as relays to close the circuit of a local battery through a call-bell and transmitter, or either.

Having now fully described my invention, I claim 1. In a telephone-signal system, the combination, with a line-wire, of a series of station apparatuses, each provided with an electromagnet connected in said line-wire and an armature controlled by said magnet and connected with a switch, whereby a single movement of the armature will cut off a fragment of the main line and ground the remainder, and a central or main station provided with means, substantially as described, for operating any particular switch through its controlling electro-magnet without disturbing intermediate switches.

2. In a telephone system, the combination, with a main line having a series of stations thereon, ofa series of electromagnetic switches of different constructions or adjustments, arranged in said line to break and close the same, and in such order that the more delicately adjusted or more easily operated switches shall be at stations more remote from a mu trai station than those of higher adjustment or requiring more force to operate them, and means at a central or main station for sending over the line an electric current suitable for operating any particular switch independently of intermediate switches, whereby the main line may be cut olf outwardly beyond any particular station without interrupting the circuit at intermediate stations.

3. The combination, with a ground-wire connected with a telephone-circuit, of an electro magnet arranged in said ground-wire, a shunt-circuit including a resistance equal to that of the magnet-coils, and a retractile armature operated by the magnet and arranged to entirely shunt the ground-circuit from its coils and to the shunt-circuit and its included resistance, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

CHARLES E. BUELL.

Witnesses:

GEORGE W. (JoY W. B. HALE. 

